The present invention relates to beta-lactamase inhibitor compounds, their production and use.
The invention and use of antibiotics to cure infectious diseases caused by bacteria is one of the milestones of modern medical and scientific technology. The beta-lactam class of antibiotics has been and continues to be one of the most important. Antibiotic resistance has become a major problem worldwide. One of the most important resistance mechanisms to beta-lactam antibiotics is the bacterial production of beta-lactamases, enzymes that inactivate beta-lactam antibiotics by catalyzing the hydrolysis of the lactam ring rendering the antibiotics ineffective towards binding of their target, penicillin binding protein.
Previous attempts to circumvent inactivation by beta-lactamases have been to alter beta-lactam compounds by functionalizing them with various organic groups conferring resistance to beta-lactam hydrolysis while maintaining antimicrobial potency. However, evolution of beta-lactamases has kept pace and there is now a beta-lactamase that is able to inactivate every known clinically available beta-lactam antibiotic; over 500 beta-lactamases have been documented.
Broadly defined by mechanism there are two fundamental classes of beta-lactamases, serine hydrolases and metallo-hydrolases. The enzymes can be further classified by subdividing them into groups according to their spectrum of activity towards beta-lactam compounds. The serine hydrolases are sub-classified into Bush Class A which are the penicillinases. Class C enzymes refer to the cephalosporinases. While Class D enzymes are the broad spectrum or extended spectrum beta-lactamases (ESBL). Bush Class B beta-lactamases refer to the metallo-enzymes that require one or two Zn2+ ions for activity and likewise show a broad spectrum of activity towards beta-lactam antibiotics. Another strategy has been to develop and use inhibitors of beta-lactamases. Three compounds are currently in clinical use, clavulanic acid, sulbactam and tazobactam.
These compounds irreversibly inhibit Class A penicillinases. Drawbacks of the known inhibitors are that they possess little intrinsic antimicrobial activity and therefore must be used in combination with beta-lactam antibiotics. The second shortcoming is that they are not clinically effective at inhibiting Classes B, C, and D enzymes which are increasingly important.
Thus, there is a significant need in the art for potent beta-lactam antibiotic compositions which demonstrate the additional functionality of potent beta-lactamase inhibition while maintaining antimicrobial potency.